If you cook at home much, you put your kitchen through the ringer with smells, smoke, and condensation. Installing a range hood is a great way to keep your kitchen, and the rest of your home, free of fumes from your stovetop. Fumes are caused by microscopic grease particles, moisture, food, and heat released as you create your delicious daily dishes. These pollutants can be harmful to the interior of your home, and also to your health. You need a hood that’ll accent and work with your kitchen’s quirks, and you’ll need to know how to determine the size, recommended power level, and ventilation system that will be most effective. We’ve outlined the basics below.
How Does a Range Hood Work?
From above or behind your stovetop, a range hood draws in air from the kitchen by use of a mechanical fan and filters out pollutants, food particles, and heat from your space as it passes through the a filter and/or duct system. You can choose to have a vented or ventless ventilation system, depending on your personal choice and spatial requirements.
Also known as “ducted,” vented hoods draw in the fumes from your kitchen and transfer them outdoors, completely removing irritants, heat and condensation from your home. This is the most effective type of ventilation system. If your range hood is mounted to an exterior wall, the vents used will be shorter and the process will be quite efficient. If mounted to an interior wall, longer ducts will be needed, as well as a more powerful system to ensure fumes are able to go the distance. If your duct runs longer than 20 feet, you’ll need an additional 100CFM in airflow capacity, plus an additional 100CFM for each 90-degree angle in the ducting. This can become difficult, so many people choose to go ventless.
Kitchen fumes are drawn through a charcoal or carbon filter that catches impurities and then re-circulates the air back into the home. This type of system doesn’t require ductwork and is much easier to install. But, it doesn’t rid your space of heat like a vented system and filters must be replaced every six months.
Some models are designed to use either filters or vents.
Types of Range Hoods
Choosing a range hood depends largely on your kitchen arrangement. A hood can be a decorative statement piece or tucked below some cabinets and out of sight … or maybe you have an island cooktop and need a hood that mounts to the ceiling. Whatever your kitchen shape, there’s a range hood ready to ventilate.
Probably the one you were picturing in your head, wall-mounted hoods give a polished, professional look to any space. These range hoods affix directly to the wall and vent up through the ceiling or through the wall. They are usually ducted straight out the back, though many have a decorative chimney, or soffit that lines up with the rest of your cabinets. You can choose whether your hood is vented or ventless, and it may have an internal or remote blower.
This is the most common type of range hood, actually. It’s installed over your stovetop and then fixed underneath cabinets, allowing some extra storage space. These hoods can be ducted directly out the back or up through the cabinet, venting through the ceiling or wall and then outdoors. They’re available in many different styles to best suit your kitchen.
A ceiling or island range hood is fixed over your kitchen’s island or peninsula and vented through the ceiling to the outdoors. This type of hood offers an attractive, contemporary look with many style options to perfectly fit your kitchen.
If you’re interested in kitchen ventilation without a permanent hood in place, the downdraft may be your perfect option. Downdraft range hoods offer a concealed look and simply pop up when needed. They can run along the back of your cook top, or front-to-back between modular stove tops. The fumes are drawn down through the floor or basement and then outdoors.
If you plan on creating your own custom hood for your space, you’ll need a ventilation power pack, which includes the blower, grease trap, lights and controls. They are intended for use in custom hood designs or uniquely shaped hoods.
Air Flow Capacity (CFM)
Airflow capacity (fan power) is measured in cubic feet per minute (CFM), which reflects the amount of air being exhausted per minute. Not only are the size and output of your range top important factors in determining CFM, but you’ll also need to consider what kind of ductwork you plan on using. The longer and more complex the ducting, the higher the CFM required.
- Heat Output: The output on your range is measured in British Thermal Units (BTUs). Divide this number by 100 for the minimum recommended CFM rating. So for example, a range with an output of 40,000 BTUs would need a hood with a CFM rating of 400 or above.
- Range and Required Hood Size: If your stove is up against a wall, you’ll need 100CFM per linear foot of range. So, for example, a range that measures 26 inches long will need a CFM of 200 or higher. Alternately, an island range needs 150CFM per foot, meaning that a 26-inch range would require a CFM of 300 or higher.
- Kitchen Size: Your range hood should be capable of fully cycling the air in your kitchen 15 times per hour (about once every 4 minutes). Divide the total volume of your kitchen (square feet x ceiling height) by 4 to get the suggested CFM. A kitchen with volume of 1400 cubic feet would need hood with a CFM of (1400 / 4) 350.
- Choose your range hood’s CFM based on the largest number of these calculations. The higher the CFM, the more effective ventilation for your kitchen will be. Just keep in mind that higher airflow capacity hoods will be louder.
Choosing the Right Size Range Hood
Measured by nominal width, a range hood’s width is measured and rounded to the next industry standard size. In order to fully capture all fumes emitted from your cooktop, the hood needs to be wider than the cooktop itself.
Consider the following measurements for the most effective setup:
- If your hood is 24-27-inches deep and CFM is 600 or more, it should be 30 inches high.
- If your hood is 22-24-inches deep and CFM is up to 500, it should be 24 inches high.
- For an electric or low-powered gas top up to 40,000 BTU, it should be 18-20 inches high.
For the most effective ventilation, leave 3 extra inches on each side of your range for your range hood.
If the hood has an airflow capacity (CFM) of over 500, 22-24 inches deep is recommended. For a CFM of 850 or over, 27 inches deep is recommended.
How to Install a Range Hood
If an old hood is still present, remove it. Under a cover near the light fixture you’ll find the electrical connection. Disconnect the wiring by removing the wire nuts and separating the connections. With a partner holding the weight of the hood, loosen the screws that support it and slide the hood off. Now remove all screws.
Open the proper venting hole and knockouts with a hammer and screwdriver. Your venting will either run up through the cabinet or through the wall, and there should be an option for either on your hood.
Mark for holes. Hold the hood in place and mark where your duct and cables will go.
If installing a new range hood system, cut holes through the drywall and drill holes at each corner through to the outside wall.
Cut siding. Connect the dots between the holes that were drilled from the inside wall and cut using a reciprocating saw. Remove any insulation or saw dust that may interfere with duct installation.
Attach duct cap to the outside wall. If it does not fully reach the range hood, purchase an extension and connect using screws and duct tape.
Apply caulk where the cap flange will rest and fasten the screws. Caulk the perimeter of the cap.
Ensuring power has been turned off, run cable from a nearby receptacle and thread through the wall, cable clamp, and small hole in the back of the hood. Strip the sheathing. The fan and light will both have a black and white wire. Connect the two black wires to the two black wires coming from the wall, and the two white wires to the two white wires coming from the wall using wire nuts. If there is an additional green wire, connect it to the grounding wire.
Tuck wires into place and mount the hood, tightening the screws.
Reattach the fan and filter, and turn on power and test it out. Ensure that the light and fan both work, and check the outside vent to see that air is flowing easily through it.